US1972982A - Carburetor - Google Patents

Description

Sept. 1l, 1934. l.. DURR GARBURETOR Filed Aug. 1s, 1929 l cu MII., 1

fnrenor Patented Sept. 11, 1934 UNITED STATES CARBURETOR Ludwig Drr,

Friedrichshafen, Germany, assigner to Luftschiibau Zeppelin Gesellschaft Mit Beschrankter Haftung, Friedrichshafen, Germany Application August 13, 1929, Serial No. 385,633

y In Germany September 13, 1928 2 claims.

My invention relates to internal combustion engines and has special reference to engines of this kind which are fed with gaseous fuel. It consists in a novel safety device.

The main object of the invention is to shut off the gas supply automatically when stopping the engine.

Another object is to have a device for this purpose which is highly reliable and also simple in construction and which cannot be brought out of order by external influences.

The drawing represents an example embodying my invention.

' Fig. 1 is an elevation, partly in section, of an arrangement of a gas flue and a mixing chamber in combination with a carburetor attached to a gas engine.

In Fig. 2 the main portion of Fig. 1 is reproduced on a larger scale.

The example is a special one in which the motor 20 can be supplied with liquid fuel, such as gasoline or the like, by means of a carburetor nozzle 3, or it can be fed by gaseous fuel entering through tube 2. The way of the gaseous fuel is indicated by arrows G, whereas arrow L points out the way in which the liquid fuel flows. Both kinds of fuels can be turned off by means of valves or cocks 5 and 25, respectively. The air to be mixed with the gaseous fuel or to flow through the carburetor 3 for Carburation with liquid fuel enters the system in the direction of arrow A and flows through a mixing chamber 4 in which it mixes with the gaseous fuel, if this is turned on.

My automatic valve 1 is situation within tube 2 which is provided with a valve seat ll'adapted for receiving valve 1. The stem 8 of valve 1 is guided in a sleeve-like portion of the small casing 9. Springs 15 with one end fastened to this casing, their other ends being fastened to valve 1, tend to hold the valve shut. The outer end of stem 8 is connected to a membrane or diaphragm 12 which may be made from metal or leather or other suitable material. This membrane is held at its circumference by means of a ring 17 and bolts or screws 18. Casing 9 together with membrane 12 confine space 13. A cover 16 encloses a second space 19 situated on the other side of membrane 12, This space 19 may or may not be connected to the open air, as circumstances may afford. Space 13 by means of bore 24 and of tube 14 is connected to the intake 7 of motor 20. Tube 14 opens into intake 7 at a point situated between throttle valve 21 and the motor 20, preferably close to the motor cylinders.

The operation of the device is as follows:

When the engine is run with gaseous fuel and consequently when the main gas valve 5 is turned on, starting of the motor effects avacuum in the intake 7. This vacuum is imparted to space 13 through tube 14 and it causes membrane 12 which is in the position represented in Fig. 1 to swing to its right hand position, as shown in Fig. 2. This movement of the membrane causes the valve 1 to open. As soon as the motor stops again the sucking effect at 7 and consequently in tube 14 vanishes and membrane 12 returns to its original position shown in Fig. 1 thereby closing valve 1.

This construction is of special importance with an arrangement as represented in Fig. 1, in which the engine can be fed with gaseous fuel or with liquid fuel, alternately. But it will also be of advantage with motors being supplied with gaseous fuel only.

The main thing is that the connection between the storage of the fuel gas and the motor is shut off automatically as soon as the motor stops. The device according to my invention has the great advantage of 4extra-ordinary reliable operation, because the working of the membrane is directly dependant on the vacuum in the intake by means of narrow tube 14 and special small space 13. Consequently, when making use of my device there will be absolute safety against fuel gas escaping into the open air.

I do not want to be limited to the details described or shown in the drawing as many variations will occur to those skilled in the art.

What I claim is:

1. 4In a fuel feeding device for an internal combustion engine, in combination, a conduit leading to the intake of said engine, means for directing liquid fuel into said conduit, means for directing air into said conduit, means for directing gaseous fuel into said conduit, a valve controlling the passage of said gaseous fuel into said conduit, a stem connected to said valve, a diaphragm connected to said stem at a point spaced from the valve, means defining a chamber with the diaphragm forming a portion of the chamber wall, a second conduit connected between said chamber and the engine intake whereby a vacuum is created in said chamber when the engine is running which will cause a pressure differential on the two sides of the diaphragm to thereby move, the diaphragm and the valve stem and hold the valve open, and spring means for closing and holding the valve closed when the vacuum is ineffective.

2. The combination recited in claim 1 wherein further the side of the diaphragm away from the chamber is surrounded by an enclosure which maintains a uniform pressure on the said side of the diaphragm and prevents any interference on the diaphragm.

LUDWIG DRR.

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